National Geographic : 1915 Dec
Photo from U. S. Department of the Interior SURVEYING ON GOLD STREAM: ALASKA The men in the picture are wearing mosquito veils. "Engineers and surveying parties waded and swam the icy waters of glacial streams, hung suspended by ropes over high precipices, and fought mosquitoes in the tundra of the lowlands and marshes, locating the line" (see text, page 567). barges to the shore at high tide, let them rest on the beach as the tide retreated, and then unload and wait for the next high tide to float them off for another load. This practice involved delays in unloading, and demurrage on steamers in those waters is from $150 to $200 a day. In constructing the temporary railroad wharves cradles, or "gridirons," were built alongside the docks, with pile foun- dations, over which the barges are floated at high water, and upon which they rest steadily as the tide recedes, the unload ing difficulties being diminished by hav ing the barges stationary while their con tents are being lifted out and placed on the dock in nets or packages by the 15 ton stiff-leg derrick. As the barges and lighters may be moved on a mean tide and taken off and onto the "gridirons"